Chamomile Tea Linked to Reduced Thyroid Cancer Risk

May 8, 2015

A small Greek case-control study found that drinking herbal teas, and in particular chamomile tea, over a long period of time is linked to a decreased risk of developing thyroid cancer and other thyroid diseases.

A small Greek case-control study found that drinking herbal teas, and in particular chamomile tea, over a long period of time is linked to a decreased risk of developing thyroid cancer and other thyroid diseases.

“Tea is one of the most commonly consumed beverages in the world, second only to water,” wrote study authors led by Athena Linos, MD, PhD, of the Institute of Preventive Medicine at Prolepsis, in Athens. Previous studies have found that tea consumption could play a role in lowering cancer risk, but few studies have looked specifically at endocrine tumors.

The new study included 113 Greek patients with histologically confirmed thyroid cancer, matched with 138 healthy control patients; the researchers also included 286 patients with benign thyroid diseases. Results were published online ahead of print in the European Journal of Public Health.

The participants were categorized according to tea consumption rates-none, at most once a week, two to six times per week, or at least once per day-and duration-0 years, at most 15 years, 15 to 30 years, and more than 30 years.

“There was a significant reduction in the odds of malignant, benign and any type of thyroid disease with an increased frequency of chamomile consumption,” the authors wrote. This association (P < .01) was seen after adjustment for age, gender, and BMI.

Those who reported drinking chamomile tea two to six times per week had an adjusted odds ratio for thyroid cancer of 0.30 (95% CI, 0.10–0.89) compared with non-drinkers. Further adjustments, for smoking, alcohol, and coffee consumption, did not change those results significantly.

The study also found an inverse association between increasing number of years of chamomile tea consumption for both malignant (P = .01) and benign (P < .001) thyroid disease. Two other types of tea, mountain tea and sage tea, also had protective effects, but not of as great a magnitude as chamomile tea.

“The generic mechanisms behind herbal tea consumption that protect from benign and malignant diseases can be attributed to anti-oxidant, anti-inflammatory, and anti-cancer activity, mainly due to the polyphenols, flavonoids and catechins that these teas contain,” the authors wrote. They noted that other factors could play a role in the reduction in thyroid cancer risk, including consumption of a Mediterranean diet. And of course, case-control studies cannot establish a definitive causative link.

Still, they concluded that “further clinical and basic studies are needed to confirm the epidemiological findings and shed light on the protective effects derived by tea consumption.”